An investigation of the structure of biological systems provides a key element in achieving an understanding of their mechanism of operation. The elucidation of the biochemical properties of such systems has usually preceeded a detailed picture of their structures. Diffraction techniques (x-ray, neutron, resonance scattering, etc.), which have become available in the past decade, promise to provide such structural detail. In this application, several qualified investigators at the University of Connecticut Health Center request addition of a major equipment item - a high brilliance, microfocus, x-ray diffraction generator (GX13 rotating anode x-ray generator) - for our ongoing studies. This proposal describes in brief the investigation of biological membrane structure and collagen and related systems of highly organized structures. The research projects pertaining to biological membrane structure require the use of a high brilliance microfocus x-ray generator for several reasons. X-ray diffraction experiments with sarcolemmal membranes show that the relatively long data collection times utilizing a low brilliance non-microfocus x-ray generator pose a severe drawback in obtaining good quality x-ray diffraction data. Similar problems exist for other biological membrane systems currently being investigated here at the Health Center. In addition, details as to relatively longlived (0.1-10 sec) agonist-induced conformational states of the acetylcholine receptor membrane can only be achieved with a high brilliance x-ray source coupled with the fast detection of x-rays utilizing a two -dimensional x-ray detector. Finally, the relatively long data collection times currently limiting research projects centered on the study of collagen and related highly organized biological structures can be overcome with the equipment requested in this proposal. Thus, high quality data can be obtained from biological membranes and highly organized biological systems before sample deterioration and with lower inherent background noise. To achieve these scientific goals relating to the structure of biological systems, a fully dedicated, high brilliance, microfocus x-ray diffraction generator is requested for the University of Connecticut Health Center. This instrument will allow several investigators at this Health Center to explore research problems not now possible with out existing outdated x-ray diffraction generator equipment.